2007 Annual Report - Central Queensland University

2007 Centre for Plant & Water Science Annual ReportACTIVATED CARBON AND ZEOLITE FILTER TRIALSUMMARYComplaints about odours from sewers increased in Brisbane during 2006 and 2007.Queensland Testing Laboratories Pty Ltd developed a prototype activated carbon and zeolitecartridge filter designed to fit into typical sewer vents and potentially reduce odours.CQUniversity tested the effect of these prototype filters with a variety of filter media.Odours from domestic sewer vents are increasing as water efficiency measures reduce thevolume of wastewater flowing through the pipe lines. The reduction in flow has lead to anincrease in the amount of solids within the pipework. The decomposition of these solidsproduces a variety of gases, not all pleasant in odour, that are released from domestic sewervents. Filters can be put on domestic vents to reduce the concentration of noxious gas release.The Queensland Testing Laboratory developed a prototype designed for 50 mm domestic sewervents. Three prototype filters were tested by CPWS with different filter media; activatedcarbon, zeolite, and an activated carbon and zeolite blend. The trial monitored the reduction inhydrogen sulphide, methane, ammonia, carbon dioxide and the impact on colony forming unitsof Escherichia coli and Salmonella sp. The filters were examined in different situations; septictanks, domestic sewer lines, and a laboratory trial. The filters were emplaced over the man-holeof the septic tank and gas release from the sludge was encouraged through the vigorous stirringof the crust. Gas from the septic tank was then pumped through the filters and concentrationsmeasured by a analytical gas-meter. Filter units were installed over three domestic sewer linesand monitored over time. For the laboratory trial mixtures of the various gases were obtained;25% methane (N 2 balance), 25% ammonia (N 2 balance), 25% hydrogen sulphide (N 2 balance),and 25% methane, 25% ammonia, and 25% hydrogen sulphide (N 2 balance). These gases wererun through the filters with the various types of filter media. All results are commercial inconfidence.Figure 1 A. Filter cartridge being weighedFigure 1B. Gas mixtures for filter trialPROJECT STAFF Principal Investigator: Ben KeleCo-Principal Investigator: David MidmoreOthers: Denis Balkin, and Robert LowryFUNDING Queensland Testing Laboratories Pty Ltd35